Nitric oxide synthase expression in ischemic rat retinas

Purpose: To investigate the expression of nitric oxide synthase (NOS) in the ischemic retina. Methods: Retinal ischemia was induced in rats by bilateral common carotid artery occlusion (BCCAO) for various lengths of time. Using the retina after BCCAO, expression of neuronal NOS (nNOS) and inducible NOS (iNOS) and identification of their positive cells were studied by histological and immunohistochemical examinations. Results: Histological examinations revealed significant reduction in the thickness of the inner plexiform layer and the outer plexiform layer of the retina. Expression of nNOS was detected in retinal ganglion cells, amacrine cells, and Muller cells after BCCAO. The expression of nNOS and iNOS detected in Muller cells became stronger and persisted long after BCCAO. Conclusions: In the ischemic retina, Muller cells and retinal ganglion cells expressed nNOS and iNOS. These phenomena may be involved in the ischemic damage to the retina. Jpn J Ophthalmol 2000;44:235-244 (C) 2000 Japanese Ophthalmological Society.